A little help

My friend has a little dog. She left in holyday and she left me the dog to take care of it. But I don’t know how to feed it and what to buy. A man helped me and told me what to buy. Wow, this food is so expensive! He helped me and gave me some dog food coupons to use them. He told me that these coupons help me to buy that food on a low price. They offer me a big discount.